Effect of systemic antibiotic and probiotic therapies as adjuvant treatments of subgingival instrumentation for periodontitis: a randomized controlled clinical study

Abstract Objective: This study assessed the efficacy of two adjunct therapies (antibiotic and probiotic) for periodontal treatment based on clinical and immunological parameters in patients with Stage II and III Grade B periodontitis. Methodology: 45 patients were randomly allocated into three groups: control group (CG); antibiotic group (GAtb), in which 500 mg amoxicillin + 400 mg metronidazole were used; and probiotic group (GProb), for which Lactobacillus reuteri was used. Patients received medications after undergoing periodontal debridement. Clinical and immunological parameters were assessed at baseline, 30 days, and 90 days. Results: All therapies reduced bleeding on probing (BoP) in the evaluated periods, and the GAtb had a greater reduction at 90 days (p=0.03). The GProb group showed better results for plaque index (PI) and gingival recession (GR) compared to the GAtb at 90 days (p=0.0014; p=0.006). The area of inflammation (PISA Index) significantly decreased in all therapies in the evaluated periods. Therapies had no significant differences regarding moderate pockets. The GAtb had a greater reduction in probing depth (PD) for deep pockets (p=0.03) at 90 days and in the number of deep pocket sites at 30 days (p=0.04). The occurrence of adverse effects was commonly reported in the GAtb as a percentage per patient. The GAtb had a significant reduction in the concentration of interleukins IL-1β and IL-8 and an increase in IL-10 and TNF-α. The CG had a reduction in IL-6 and IL-1 β, whereas in the GProb there was no difference. Conclusion: After three months, none of the adjuvant therapies provided any additional benefit for subgingival instrumentation.

dyscrasias, and immunodeficiencies, among others) that contraindicated the periodontal procedure; 2) had underwent periodontal treatment in the last 12 months; 3) had used antibiotics, antiinflammatories, or probiotic supplements in the last 6 months; 4) were smokers; 5) were pregnant or lactating; and 6) chronically used medications that could affect the periodontal response.
Initial therapy All patients received information regarding their periodontal condition and oral hygiene guidelines.
Biofilm, supragingival calculus, teeth indicated for extraction, and excessive restorations were removed, and endodontic treatments and cavity filling were performed.

Clinical measures
All clinical measurements were performed by a single investigator (TCSR) previously calibrated and blinded to the treatment received by the patients.

Statistical analysis
The data obtained after each assessment were subjected to statistical analysis. Descriptive statistics consisted of calculating means and standard deviations, and inferential statistics were performed first using the Shapiro-Wilk test to verify data normality. Since the data were not normal, nonparametric tests were used. The Kruskal-Wallis test of variance, performed in the BioEstat 5.3 software (BioEstat 5.3, Belém, PA, Brazil), and the Dunn post hoc test were used for multiple comparisons, both with a significance level of 5% to assess the inter-group comparison. The chi-square test was used to assess inter-group differences regarding qualitative variables. For the intra-group comparison, the Friedman test was used with a significance level of 5%. For data with normal distribution, one-way ANOVA tests were used.

Results
Forty-five patients were included and remained present at all follow-ups performed in the study (baseline, 30 days, and 90 days). Figure 1 shows the flowchart of the distinct phases of the study. Bleeding on Probing (BoP) and Plaque Index (PI) Table 2 shows that BoP decreased 30 and 90 days after the baseline in all intra-group comparisons. BoP reduction was more significant in the GAtb than in the GProb only at 90 days (p=0.03) of procedure.
Out of the three groups, only control and probiotic groups had intra-group differences in PI. In the inter-group assessment, CG and GProb had a greater plaque index reduction (p=0.008) after 30 days.
Gprob also had the best plaque control (p=0.001) after 90 days.

Probing depth (PD)
Intra-group comparisons between baseline vs 30 days and baseline vs 90 days showed a significant reduction in total PD in the 3 groups (p<0.0001).
The groups had no significant difference between each other during the experimental period (Table 2).

Clinical attachment level (CAL)
In all groups, a significant full-mouth attachment gain was observed between the baseline vs 30 days and baseline vs 90 days periods (p<0.05). The groups had no significant difference between each other regarding CAL. Gingival recession (GR) GR significantly increased in all groups. In intergroup comparisons, the GProb gingival recession was lower than GAtb at 30 days (p=0.03) and lower than both therapies at 90 days (p=0.006).

Periodontal Inflamed Surface Area (PISA) Index
The PISA Index showed no statistically significant difference in the inter-group comparison; the intra-group comparison, however, showed PISA differences between baseline vs 30 days and baseline vs 90 days (p<0.05) (Table 3).

Moderate and deep pockets
All treatments showed a significant reduction for CAL, PD, and the number of sites with moderate and deep pockets in the intra-group comparison. In the  inter-group comparison, the mean probing depth and the number of sites of moderate pockets (5 and 6 mm) had no significant differences (Table 4)        The GAtb showed a higher frequency of adverse effects during the medication administration period than the GProb, whose patients reported no adverse effects. The most reported adverse effects by GAtb patients were headaches (60%), metallic taste in the mouth (33%), and nausea or vomiting and diarrhea or abdominal pain (27%). The occurrence of these effects corroborates with the data in the literature. 2,23 Although its effects are less evident than those of other therapies, treatment with probiotics has shown better results than debridement alone and causes no adverse effects. Therapy with antibiotics is still the most effective, despite causing adverse effects in many patients. We suggest that future studies conduct microbiological evaluations since they allowed us to understand reasons of less biofilm in our results.
This study's limitation is the reduced follow-up time since activities were suspended because of the COVID-19 pandemic. We suggest non-inferiority trials to observe if probiotics are inferior or not to antibiotics regarding benefits to the periodontal treatment and having less adverse or side effects.

Conclusion
We conclude that none of the adjuvant therapies